ALK and neoplasm: All 53 ALK amino acid substitutions had tumor mutant allele frequency (MAF) values ranging from 0.034 to 0.568, classifying them as rare or less frequent alleles in the population, in the context of TCGA data, MAF or also known as “variant allele frequency” (VAF) refers to the proportion of reads at a specific genomic location that carry a somatic mutation, indicating the percentage of tumour cells harbouring that mutation.